1. Field of the Invention
The present invention relates to a quantity-of-light adjusting device for use in a video camera, a digital still camera or the like.
2. Description of Relates Art
For motion-image taking cameras such as video cameras, there is used a motion-image quantity-of-light adjusting device which continuously varies a diaphragm aperture from a full-aperture state up to a full-closed state. On the other hand, for still-image taking cameras such as digital still cameras, there is used a still-image quantity-of-light adjusting device which switches a diaphragm aperture between two positions, i.e., a full-aperture state and a small-aperture state (e.g., F8) or which is capable of performing a shutter action in addition to the quantity-of-light adjusting function.
Further, a quantity-of-light adjusting device which is capable of adjusting a diaphragm aperture to at least three positions by means of a turret diaphragm mechanism is disclosed in, for example, Japanese Laid-Open Utility Model Application No. HEI 3-52725. In this quantity-of-light adjusting device, a mechanical diaphragm mechanism is used to mechanically restrict a diaphragm member to the full-aperture position by means of a torsion spring and this position is changed over to another position by transmitting a driving force of a driving part to the diaphragm member through gears.